Messages in this thread | | | Date | Wed, 26 Mar 2014 14:20:42 +0800 | From | Josh Wu <> | Subject | Re: [PATCH] [media] ov2640: add support for async device registration |
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Hi, Sylwester
On 3/20/2014 10:44 PM, Sylwester Nawrocki wrote: > Hi Josh, > > On 19/03/14 10:17, Josh Wu wrote: >> On 3/15/2014 5:17 AM, Sylwester Nawrocki wrote: >>>> On 03/14/2014 11:12 AM, Josh Wu wrote: >>>>>> + clk = v4l2_clk_get(&client->dev, "mclk"); >>>>>> + if (IS_ERR(clk)) >>>>>> + return -EPROBE_DEFER; >>>> You should instead make it: >>>> >>>> return PTR_ERR(clk); >>>> >>>> But you will need this patch for that to work: >>>> http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/clk/clk.c?id=a34cd4666f3da84228a82f70c94b8d9b692034ea >>>> >>>> >>>> With this patch there is no need to overwrite any returned error >>>> value with EPROBE_DEFER. >> Thanks for the information. I will use this in v2 version. > Oops, I missed somehow that it's v4l2_clk_get(), rather than > clk_get(). So it seems it will not work when you return PTR_ERR(clk), > since v4l2_clk_get() returns -ENODEV when clock is not found.
right, I missed that. So this version is still valid one. The v2 that I already sent should be dropped.
> I think we should modify v4l2_clk_get() so it returns EPROBE_DEFER > rather than ENODEV on error. I anticipate v4l2_clk_get() might be > using clk_get() internally in future, and the v4l2 clk look up > will be used as a fallback only. So sensor drivers should just > do something like: > > clk = v4l2_clk_get(...); > if (IS_ERR(clk)) > return PTR_ERR(clk);
I noticed that there are some driver like ov772x, ov9640 and etc, are not supported the async probe yet. If we return the EPROBE_DEFER for all v4l2_clk_get(), that will cause the no-async probe function work incorrectly. So IMO we can do your above suggestion after all sensors support async probe.
Thanks. > > -- > Regards, > Sylwester
Best Regards, Josh Wu
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